The present invention relates to the design of a system solution including an active tag used to track Unit Loading Devices [ULD's] and ULD pallets during the storage and cargo handling process in aviation applications. The tag is designed with unique physical and operational characteristics that when combined permit: long extended battery life, identification of pallets and ULD's at portals, track and trace of pallets and ULD's in motion on dollies when used to transport cargo to aircraft. When the defined features are used in combination, identification and tracking of the pallets and ULD is achieved during storage, processing, travel to and from and placement within aircraft without the need to transmit continuously.
The objective of the stated invention is to permit automatic track and trace of Aluminum pallets and ULD's used to transport cargo in aircraft during processing and storage. Prerequisites to such an application demand a tag solution with unique and innovative features. These include: Mechanical protection of the tag without causing obstruction or altering the pallet profile and maintaining the structural integrity of the aluminum pallet; a mechanism for eliminating or control of transmission of the tag onboard the aircraft; identification of multiple pallets when stacked on one another; means of determining the direction of flow and open side of the ULD as they move down a conveyer system; identification of pallets as they pass specific points or points of handover; identification of pallets and ULD's when on the apron of the airfield being ready for loading or after being unloaded; and a 5 year operational life.
There are systems in place to collect the time and position of an object automatically. This equipment is typically installed throughout industrial and commercial facilities and permits automated collection or measurement of time of arrival data. Such equipment, composed of antennas and readers are positioned at portals covering points of entry or in a cellular fashion.
Presently, corresponding tags are available in various formats including active tags with batteries, passive tags where the tags are powered by incident energy and semi-active tags where an integrated battery assists in the powering of the tag circuitry. Each of these solutions work well in specific environments. However the combined demands of cargo transport in the aviation environment, as enumerated above, requires a unique innovative solution.
It is known in the prior art for tag reader systems to rely on the frequency independence of the incident signal to the response signal. This is referred to in the industry as a dual frequency solution or dual independent stimulus solution. There is no relationship in time or mathematically between the incident wake up signal and response signal.